Asphaltic filament comprising asphalt, ethylene-vinyl acetate copolymer and paraffinwax



United States Patent 3,291 ,767 Patented Dec. 13, 1966 "ice 1 having softening points (ring and ball) of 230290 F.

3,291,767 ASPHALTIC FILAMENT COMPRISING ASPHALT, ETHYLENE-VINYL ACETATE COPOLYMER AND PARAFFIN WAX 5 Ralph Zaayenga, Media, Pa., assignor to Sun Oil Company, Philadelphia, Pa., a corporation of New Jersey No Drawing. Filed July 16, 1963, Ser. No. 295,499 2 Claims. (Cl. 260-285) This invention relates to a filament containing a major proportion of asphalt together with minor proportions of paraflin wax and a copolymer of ethylene and vinyl acetate. The filament can also contain a minor proportion of a plasticizer.

Asphalt filaments have been prepared in the past as shown by US. Patents 1,289,892 and 1,352,623. These filaments, however, are quite short, i.e., less than a few inches in length, and they are very fragile.

We have developed a filament containing a major proportion asphalt and waxboth low cost materials strengthened with a copolymer resin, which can be provided in almost any desired length. The filament of the invention is non-tacky, and strands do not stick together at temperatures in the range of 100 to 150 F. These properties are critical when the material is used to prepare such products as packing materials, batts and mulches.

Suitable asphalts are those derived from petroleum refining operations such as vacuum distillation, solvent extraction, i.e., propane deasphalting and oxidation processes or combinations of these. The asphalt must have a softening pointring and ball in the range of about 200-300 F. to be suitable for the continuous, flexible If desired plasticizers and extenders can be added in small amounts, i.e., 10-30 wt. percent, to achieve desired effects. Examples include atactic polypropylene, polyoctene, polybutene, polyisobutylene, styrene-butadiene copolymers, heavy aromatic oils, petroleum resins, formolite-type resins and the like.

The ingredients are blended in any suitable equipment by heating and stirring at temperatures ranging from 275- 450 F. The preferred procedure is to heat the asphalt to the desired temperature and add the other ingredients. The filaments can be prepared in conventional filament forming equipment.

The invention will be more readily understood by referring to the following illustrative examples:

Six hundred grams of air blown asphalt having a melt point of 25 0 F. was heated in a container to a temperature of 320 P. Then 200 grams of ethylene-vinyl acetate copolymer having a softening point of 276 F. and 200 grams of Wax having a melt point of 127 F. were stirred into the asphalt. The blend was cooled and cut into rods. The rods were fed into a inch diameter standard plastics extruder having a length to diameter ratio of 12. The extruder contained no breaker plate or screen pack. The gears were set to give slow screw feeds. The die head was maintained at 350 F. employing electrical heating. An air stream was maintained about two feet below the die head to blow the filament out in a horizontal direction. With this set up, filaments ranging from 3-15 feet in length having a diameter of .001 to 0.2 inch were provided without difliculty. With more sophisticated equipment it is possible to make filaments of any desired length, and these can be wound up on rolls without sticking.

The following table shows the results obtained with filaments of the invention. The composition contains at various f l ti Ingredients are i wt. percent.

Table I Et y v Filament Pro ert'es High Blown acetate Carbon Black Atacti W 3425 P V,C, Clay p 1 Asphalt Oopolymer Oil RP.

Flexible Tacky Asphaltene.

least 50 wt. percent asphalt, and the preferred range is 5075 wt. percent.

Suitable waxes are the paraflin waves obtained in petroleum refining operations. Waxes having melt points of 125-160 F. (ASTM D8.7-57) and viscosities of 30-50 Saybolt Universal seconds at 210 F. (ASTM D446-53) are preferred. From 10 to 20 wt. percent wax is used in the filaments.

Our filaments also contain ethylene-vinyl acetate copolymers. One method of preparing the copolymers is disclosed in US. Patent No. 2,200,429 to Perrin et a1. Generally, the preparation involves copolymerizing a mixture of ethylene and vinyl acetate by means of a freeradical producing catalyst, such as oxygen or an organic peroxide, at a pressure of 100 to 200 atmospheres and a temperature in the range of 150 to 250 C. and recovering the product. The proportion of ethylene to vinyl acetate in the resin can be varied considerably. For purposes of the present invention the resin contain from 5 to 15 moles of ethylene per mole of vinyl acetate. Particularly suitable ethylene-vinyl acetate copolymers are those The above data show that flexible non-tacky continuous filaments are obtained only when'asphalt, parafiin wax and ethylene-vinyl acetate copolymer are employed in certain relative quantities.

I claim:

1. A substantially continuous flexible, non-tacky filament comprising from 50 to Wt. percent asphalt having a softening point of at least 200 F., from 10 to 20 wt. percent paraflin wax having a melt point of at least F. and from 1 to 20 wt. percent of an ethylene-vinyl acetate copolymer resin having a softening point of 200- 300 F.

2. A substantially continuous flexible, non-tacky filament having a diameter of .001 to .02 inch comprising from 50 to 75 wt. percent asphalt having a softening point of 200-300 F., from 10-20 wt. percent paraflin wax having a melt point of 125160 F. and from 10-20 wt. percent of an ethylene-vinyl acetate copolymer resin having a softening point of 200-300 F. and containing 5 to 15 moles of ethylene per mole of vinyl acetate said filament 3,291,767 a. 4 being characterized by the ability to be wound on a one FOREIGN PATENTS inch-- diameter"spoo1' and unwound therefrom without 594 /1 65 d breaking or sticking at a temperature of 100-150 F. 9 s

OTHER REFERENCES References Cited by the Examiner 5 Abraham: Asphalts and Allied Substances, Van

UNITED STATES PATENTS I Nostrand, N.Y., 1960, vol. 3, pages 80, 245. 3,177,164 4/1965 M1118 et a1 '260 2.5 MORRIS HERMAN Prlmay 3 191426 7/ 1965 Zaayenga 26028.5 J. A. GAZEWOOD, Assistant Examiner. 

2. A SUBSTANTIALLY CONTINUOUS FLEXIBLE, NON-TACKY FILAMENT HAVING A DIAMETER OF .001 TO .02 INCH COMPRISING FROM 50 TO 75 WT. PERCENT ASPHALT HAVING A SOFTENING POINT OF 200-300*F., FROM 10-20 WT. PERCENT PARAFFIN WAX HAVING A MELT POINT OF 125-160*F. AND FROM 10-20 WT. PERCENT OF AN ETHYLENE-VINLY ACETATE COPOLYMER RESIN HAVING A SOFTENING POINT OF 200-300*F. AND CONTAINING 5 TO 15 MOLES OF ETHYLENE PER MOLE OF VINYL ACETATE SAID FILAMENT BEING CHARACTERIZED BY THE ABILITY TO BE WOUND ON A ONE INCH DIAMETER SPOOL AND UNWOUND THEREFROM WITHOUT BREAKING OR STICKING AT A TEMPERATURE OF 100-150*F. 